1. Field of the Invention
The present invention relates generally to erbium doped fiber amplifiers for optical networks, particularly dense wavelength multiplexed networks.
2. Description of Background Art
Dense wavelength multiplexed (DWDM) networks are of interest for a variety of applications. Conventionally, for example, optical multiplexers with a low insertion loss are used to multiplex wavelength channels, resulting in a high cost for each optical multiplexer. Erbium doped fiber amplifiers (EDFAs) are commonly used to amplify bands of wavelength channels. For example, a single EDFA may be configured to provide power amplification for a band consisting of a few closely spaced wavelength channels (e.g., 3–5). Alternatively a single EDFA may be configured to provide high gain at low power levels. Consequently, a conventional DWDM network may use several different types of EDFA amplifiers, such as pre-amplifiers, post-amplifiers, and EDFAs for providing amplification to a small number of wavelength channels.
The component cost of DWDM networks is greater than desired, particularly for DWDM networks designed to accommodate 20 or more wavelength channels. Conventionally, low-insertion loss optical multiplexers are required along with a substantial number of EDFAs of different types. As result, the component cost is greater is greater than desired for many applications.
What is desired is a DWDM network with reduced component cost.